Sheriff Woody is doing his durnedest to save the world from Hamm the piggy bank, alias Dr. Evil Porkchop  "That's Mister Dr. Evil Porkchop to you!"  before the Old West train Woody's on and the orphans inside crash to their doom. His cowgal pal Jessie rides to the rescue, and space ranger Buzz Lightyear is, as always, eager to take his friends "to infinity  and beyond!" But even they may be no match for the spaceship that descends and, when its doors open, reveals ...

... Reveals, in the first scene of Toy Story 3, that the boy Andy has a terrific time playing with his toys. In a bedroom strewn with all kinds of characters, from cowboys and astromen to a Slinky dog and Mr. and Mrs. Potato Head, the 7-year-old mashes genres together to accommodate them all. Toys trigger what the movie's director, Lee Unkrich, calls a child's "crazy, non sequitur imagination." They unlock his creativity, let him play out elaborate scenarios inspired by films and TV shows he's seen and then remade in the wild innocence of a young mind  one that knows all the rules of narrative but doesn't mind smashing them with Dadaist abandon. (See a photographic history of Pixar.)

That's the creative strategy at Pixar, which produced the first computer-animated feature, Toy Story, in 1995 and has bloomed ever since, through Finding Nemo, WALLE and last year's Up. Pixar filmmakers have to be able to tap into their vestigial child, their inner Andy. In that sense, the Toy Story series is their collective autobiography. Like Andy, the Pixarians  from creative director John Lasseter on down  are smart kids who never renounced their childish belief that anything is possible. Why, to make an instant classic like Toy Story 3, it just takes an unfettered imagination, several hundred artists and technicians, about $200 million and four years of nonstop work. Child's play.

In 15 years, the Pixar unit has produced just 11 features. The first 10  Toy Story; A Bug's Life; Toy Story 2; Monsters, Inc.; Finding Nemo; The Incredibles; Cars; Ratatouille; WALLE and Up  are not just some of the best computer-animated films but some of the liveliest, brightest, most heartfelt movies of the recent past. That they have earned lots of money ($5.6 billion worldwide) for Pixar and its parent company, Disney, is almost beside the point. Like the earliest Walt Disney fables, Pixar films are for children and their parents and everyone who can be touched by moving images. "We don't make movies for kids," Unkrich says emphatically. "Our mission statement is to make films for everybody." That includes the Motion Picture Academy: Pixar has won five of the nine Oscars for Best Animated Feature and the last three in a row. (See the top 10 voices behind Pixar characters.)

Okay, but a third Toy Story, from a studio where nine of the first 10 features were total originals? Lasseter, who directed and co-wrote the first two Toy Story films and who's supervising second episodes of Cars and Monsters, Inc., allows that some people "make sequels as a way of printing money, and they tend to rehash the same idea." He insists Pixar returns to favorite characters because "they are alive in us. We think of them as friends and family. We want to see what new, deeper emotions we can find."

For Toy Story 3's screenwriter Michael Arndt (who won an Oscar for writing Little Miss Sunshine), that meant rethinking each old toy and finding unsuspected human wrinkles. The film's visual style, bracingly clear in its 3-D version, is both state-of-the-CGI-art and faithful to the simple design of the first two films. "I wanted it to look great," says Unkrich, who served as editor on the first Toy Story and co-director on the second. "But it also had to look like Toy Story." What's more potent is the upping of the emotional ante. TS3 puts its characters and the moviegoing children who love them in their severest crisis yet. Not since the early Disney classics have cartoon characters faced so dire a threat with such heroic grace. Lasseter recalls a meeting of the Pixar brain trust for the first reading of the story. "By the end," he says, "I had tears streaming down my face. I looked around the table, and we all had tears."